An efficient synthesis of cis-2-amino-1-fluorocyclobutane-1-carboxylic acid in single enantiomer form was established and protected homo-oligomers (2-, 4-, and 6-mers) of this cyclic cis-b-amino acid were prepared. Conformational analysis of these oligomers using IR, NMR and CD techniques in solution, supported by molecular modelling studies, suggested a strong conformational preference for a welldefined strand-like structure in which intra-residue hydrogen bonding is weak at best and is not consequential for adoption of the secondary structure. Single crystal X-ray analysis of the tetramer showed that a regular strand-like conformation is adopted in the solid state; only intermolecular hydrogen bonding networks are observed. The backbone topology and the 4-membered ring orientations are noticeably different from those of the tetramer of the corresponding non-fluorinated cis-b-amino acid.

A series of pyridinium-betaine like molecules has been reported; one family of molecules is built with a benzimidazole core and a second one with a pyrimidine moiety. The title compounds were prepared by mixing 2-chlorobenzimidazole or 2-bromopyrimidine with the corresponding pyridines (pyridine, 4-tert-butylpyridine, 4-hydroxypyridine, potassium 4-trifluoroboratepyridine, 4-dimethylaminopyridine) in acetonitrile or DMSO at high temperatures. The novel compounds were characterized by spectroscopic methods. The UV-Vis. and fluorescence features are reported as well. Preliminary photoluminescence results showed broadband emissions as common feature ascribed to the compounds containing benzimidazole ring. Some of the spectra nearly span over the whole visible spectral range, which pave the way to real opportunities to design single-component panchromatic emitters.

Two coordination polymers of coinage metals with a rare pyridinium-betainoid L assembling ligand are reported. These polymers are obtained by self-assembly of the linker L and copper(I) or silver(I) ions in acetonitrile. The compounds were characterized by spectroscopic methods and by elemental analysis. The solid-state structures were unambiguously confirmed by single crystal diffraction studies. These assemblies exhibit original helicoidal arrangements. The UV-Vis. absorption and photoluminescence properties are reported as well.